Endo - Physiology (Adrenal)

Question 1

What regulates cholesterol desmolase in the adrenal cortex, and how so?

Answer 1

ACTH stimulates, Ketoconazole inhibits

Question 2

What reaction does cholesterol desmolase catalyze in the adrenal cortex? Towards what final product does this reaction contribute? Where is this produced?

Answer 2

Cholesterol –> Pregnenolone; Aldosterone; Zona Glomerulosa

Question 3

What 3 reactions does 3Beta-hydroxysteroid dehydrogenase catalyze in the adrenal cortex? Towards what final product does each of these reactions contribute? Where are each of these final products produced?

Answer 3

(1) Pregnenolone => Progesterone; Aldosterone (Zona Glomerulosa) (2) 17-hydroxypregenolone => 17-hydroxyprogesterone; Cortisol (Zona Fasciculata) (3) Dehydroepiandrosterone (DHEA) => Androstenedione; Testosterone/Estradiol (Zona Reticularis)

Question 4

What 2 reactions does 21-hydroxylase catalyze in the adrenal cortex? Towards what final product does each of these reactions contribute? Where are each of these final products produced?

Answer 4

(1) Progesterone => 11-deoxycorticosterone; Aldosterone (Zona Glomerulosa) (2) 17-hydroxyprogesterone => 11-deoxycortisol; Cortisol (Zona Fasciculata)

Question 5

What 2 reactions does 11Beta-hydroxylase catalyze in the adrenal cortex? Towards what final product does each of these reactions contribute? Where is each produced?

Answer 5

(1) 11-deoxycorticosterone => corticosterone; Aldosterone (Zona Glomerulosa) (2) 11-deoxycortisol => Cortisol; Cortisol (Zona Fasciculata)

Question 6

What reaction does Aldosterone synthase catalyze in the adrenal cortex? Towards what final product does this reaction contribute? Where is it produced?

Answer 6

Corticosterone => Aldosterone; Aldosterone (Zona Glomerulosa)

Question 7

What regulates Aldosterone synthase in the adrenal cortex, and how?

Answer 7

Angiotensin II stimulates

Question 8

What 2 reactions does 17alpha-hydroxylase catalyze in the adrenal cortex? Towards what final product does each of these reactions contribute? Where are each of these reactants and final products found?

Answer 8

(1) Pregenolone (Zona Glomerulosa) => 17-hydroxypregenolone (Zona Fasciculata) => Dehydroepiandrosterone (DHEA) (Zona Reticularis) (2) Progesterone (Zona Glomerulosa) => 17-hydroxyprogesterone (Zona Fasciculata) => Andostenedione (Zona Reticularis)

Question 9

What type of substances is produced in each of the following zones of the adrenal cortex: (1) Zona Glomerulosa (2) Zona Fasciculata (3) Zona Reticularis?

Answer 9

(1) Mineralocorticoids (2) Glucocorticoids (3) Androgens

Question 10

What is the progression of dihydroepiandrosterone (DHEA) to testosterone? Where does this occur in the adrenal cortex?

Answer 10

Dehydroepiandrosterone (DHEA) => Androstenedione => Testosterone; Zona Reticularis

Question 11

What 3 sex hormones are produced in the peripheral tissue following conversion from a precursor in the adrenal cortex? What are each of their precursors, and what enzymes catalyze each of these reactions? Where in the adrenal cortex are all of the precursors located?

Answer 11

(1) Estrone; Aromatase coverts Androstenedione to Estrone (2) Estradiol; Aromatase converts Testosterone to Estradiol (3) Dihydrotestosterone (DHT); 5alpha-reductase converts Testosterone to Dihydrotestosterone (DHT)

Question 12

In 17alpha-hydroxylase deficiency, how are the levels of each of the following changed: (1) Mineralcorticoids (2) Cortisol (3) Sex hormones.

Answer 12

(1) Increased (2) Decreased (3) Decreased

Question 13

In 21-hydroxylase deficiency, how are the levels of each of the following changed: (1) Mineralcorticoids (2) Cortisol (3) Sex hormones.

Answer 13

(1) Decreased (2) Decreased (3) Increased

Question 14

In 11beta-hydroxylase deficiency, how are the levels of each of the following changed: (1) Mineralcorticoids (2) Cortisol (3) Sex hormones.

Answer 14

(1) Decreased aldosterone, Increased 11-deoxycorticosterone (results in high BP) (2) Decreased (3) Increased

Question 15

Again, what are the changes in mineralcorticoids in patients with 11beta-hydroxylase deficiency? Be specific. What effect does this have?

Answer 15

Decreased aldosterone, Increased 11-deoxycorticosterone (results in high BP)

Question 16

What are 3 key lab findings that characterize 17alpha-hydroxylase deficiency?

Answer 16

(1) Hypertension (2) Hypokalemia (3) Low DHT

Question 17

What are 4 key lab findings that characterize 21-hydroxylase deficiency?

Answer 17

(1) Hypotension (2) Hyperkalemia (3) High renin activity (4) High 17-hydroxyprogesterone

Question 18

What 2 key lab findings characterize 11beta-hydroxylase deficiency, and why?

Answer 18

Hypertension (low renin)

Question 19

What changes occur to adrenal glands in response to congenital adrenal enzyme deficiencies, and why?

Answer 19

All congenital adrenal enzyme deficiencies are characterized by an enlargement of both adrenal glands due to increase ACTH stimulation (due to decreased cortisol).

Question 20

What is (are) the defining physical presentation(s) in patients with 17alpha-hydroxylase deficiency?

Answer 20

XY: pseudohermaphroditism (ambiguous genitalia, undescended testes); XY: lack secondary sexual development

Question 21

What is (are) the defining physical presentation(s) in patients with 21-hydroxylase deficiency?

Answer 21

Presents in infancy (salt wasting) or childhood (precious puberty); XX: virilization

Question 22

What is the defining physical presentation in patients with 11beta-hydroxylase deficiency?

Answer 22

XX: virilization

Question 23

What is the source of cortisol?

Answer 23

Adrenal zona fasciculata

Question 24

What are 6 major functions of cortisol?

Answer 24

(1) Increase blood pressure (upregulates alpha1-receptors on arterioles => increased sensitivity to norepinephrine and epineprhine) (2) Increase insulin resistance (diabetogenic) (3) Increase gluconeogenesis, lipolysis, and proteolysis (4) Decrease fibroblast activity (causing striae) (5) Decrease inflammatory and immune responses (A - inhibits production of leukotrienes and prostaglandins, B - Inhibits leukocyte adhesion => neutrophila, C - Blocks histamine release from mast cells, D - Reduces eosinophils, E - Blocks IL-2 production) (5) Decrease bone formation (decrease osteoblast activity); Think: “cortisol is a BIG FIB = Bp high, Insulin resistance, Gluconeogenesis etc., Fibroblast low, Inflammation/Immune low, Bone formation low.

Question 25

What effect can exogenous corticosteroids cause, and why?

Answer 25

Exogenous corticosteroids can cause reactivation of TB and candidiasis (blocked IL2 production)

Question 26

What causes the release of cortisol, and from where?

Answer 26

CRH (hypothalamus) stimulates ACTH release (pituitary), causing cortisol production in adrenal zona fasciculata

Question 27

What relationship does chronic stress have with cortisol?

Answer 27

Chronic stress induces prolonged secretion

Question 28

What hormonal/molecular effects does excess cortisol secretion have?

Answer 28

Excess cortisol decreases CRH, ACTH, and cortisol secretion